Methods for resist stripping and cleaning surfaces substantially free of contaminants

ABSTRACT

A plasma assisted cryogenic cleaner for and a method of performing cleaning of a surface that must be substantially free of contaminants has a resiliently mounted nozzle for spraying a cryogenic cleaning medium on the surface. The cleaning is conducted by applying to the substrate surface a mixture of gases selected from the group consisting of oxygen, nitrogen, hydrogen, fluorine, hydrofluorocarbon or a mixture of such gases to both remove the photoresist layer and alter the composition of the residues such that the residues are soluble in water and/or have a weakened bonds that they can be removed with a stream of cryogenic medium. The cryogenic and plasma processes can be performed sequentially or simultaneously. In certain embodiments, the cryogenic cleaning medium nozzle is driven in an oscillatory or vibratory manner so the nozzle spray is delivered in a manner to provide pulsing of the spray and to provide as “snow plow” effect on contaminants as the spray delivers the cleaning medium against the surface. The surface may be transported past the nozzle, and the cleaning may occur in an enclosed controlled environment.

FIELD OF THE INVENTION

This invention relates to systems and methods for removing photoresistfrom an integrated circuit structure with a dry process, preferably, ina vacuum stripping chamber, such as photoresist remaining after etch,implant or other fabrication steps. The invented system and method alsoremove etch residues remaining from the previous fabrication step(s).The present invention also is suitable for cleaning surfaces on harddisks, semiconductor wafers, delicate optics, etc. The present inventionmore particularly relates to a preferably oscillating nozzle cleaningsystem, preferably dispensing cryogenic, solvent or solvent combinationcleaning mediums, combined with plasma excited reactive gases. Theoscillating nozzle cleaning and plasma processes can be performedsequentially or simultaneously.

BACKGROUND OF THE INVENTION

Articles such as hard disks, semiconductor wafers, delicate optics,etc., often must be precisely cleaned in order to remove contaminants,either during or after a process for manufacturing the articles. Forexample, resist strip and residue clean typically are needed betweenetch, implant and deposition steps in IC fabrication processes.Conventional dry-type strip/clean sequences typically use plasma to ashresist and wet chemicals to clean residues. Resist stripping istypically carried out using dry plasma ashing. Conventional O₂ plasmaashing at high temperature tends to leave polymeric residues thatrequire acids and/or organic solvents for removal. Wet chemistriesgenerally are not desirable due to non-uniformities, selectivity toexposed layers and incomplete resist removal because of mass transportand surface tension associated with the solutions. A variety ofalternative cleaning methods have been employed with varying degrees ofsuccess. Certain of such methods that have been attempted involveimparting carbon dioxide snow onto the article to be cleaned.

An example of such a conventional carbon dioxide cleaning system isdescribed in U.S. Pat. No. 5,766,061. As a general/summary descriptionof this system, a conveyor transports a wafer-carrying cassette to becleaned in an enclosure. Jet spray nozzles generate carbon dioxide spraythat cleans the wafers. While methods such as described in this patentprovide a certain level of cleaning efficacy, improved methods forcleaning a variety of articles are still very much in demand. Inaddition, conventional jet spray nozzle approaches, while effective insome applications, generally fail in the majority of applications wherethe bonding between the surface of the wafer and the contamination onthe wafer are strong and require chemical reaction, such as plasma, aswell as a physical cleaning mechanism for adequate de-contamination andremoval of residues, etc.

SUMMARY OF THE INVENTION

The present invention relates to systems and methods preferably using aplasma generation system, as a chemical means, for resist and polymerresidue removal and a preferably cryogenic cleaning medium, as aphysical means, for enhancing the cleaning of an exposed surface of anarticle. The cryogenic cleaning medium also helps in reducing submicrondefects. The plasma source preferably is either a remote source thatprovides free-radicals or an ion assisted chemistry activated by directexposure of the wafer to an RF plasma. In certain preferred embodiments,the free radicals/ions ratio can be controlled by running simultaneouslyboth sources (remote and RF sources). The cryogenic and plasma processescan be performed sequentially or simultaneously in the same chamber orin two separate chambers.

A summary of an exemplary preferred embodiment is as follows. Anenclosure is provided for maintaining a controlled environment duringthe photoresist stripping and post etch, implant or other fabricationstep residue cleaning process. The enclosure preferably provides ingressand egress from and to a surrounding environment. A holding chuckpreferably is provided that is configured to secure the article to becleaned of photoresist and/or remaining polymeric residue. Theenvironment preferably is pressure controlled (vacuum) to optimizeplasma reaction. A stage or stage means is mounted on the supportstructure and the holding chuck is mounted on the stage means in amanner so that movement of the article relative to the support structureis provided within the enclosure on a predetermined path between theingress and the egress points. The stage or stage means, in alternativeembodiments, is fixed and the system allows the nozzle to move relativeto it for complete surface coverage of the cryogenic gas. A pre-heater,in certain embodiments, is mounted in a first position adjacent thepredetermined path in thermal communication with the surface of thearticle at the first position. Reactive gases such as oxygen preferablyare introduced through a remote plasma chamber. The processing chamberis connected to a vacuum exhaust line. A cryogenic spray nozzle assemblypreferably is provided wherein a spray nozzle is mounted in the spraynozzle assembly. The spray nozzle is in communication with the cryogeniccleansing medium for providing a cleaning spray at a second positionadjacent the predetermined path so that the cleaning spray impinges onthe surface to be cleaned at the second position. A post heateroptionally is provided and, if so provided, preferably mounted in athird position adjacent to the predetermined path in thermalcommunication with the surface of the article at the third position. Thecryogenic spray nozzle assembly, in preferred embodiments, furtherincludes an assembly or other means for imparting cyclic motion in thespray nozzle so that the cleaning spray is moved bi-directionallyrelative to the predetermined path. This cyclic motion assembly or meansalternatively could be external to the environment.

In another aspect of the present invention, systems and methods areprovided for cleaning a surface of an article, wherein a preferredsystem includes a framework, a holding means that holds the article withthe surface exposed, and means for moving the holding means along apredetermined path. The plasma source preferably is separated remotelyfrom the article that is being processed, with free radicals generatedremotely. Ion assisted chemistry, optionally or in combination with theremotely generated free radicals, are provided preferably by directexposure of the wafer to an RF plasma. The plasma also may be activatedby both a remote source and an RF plasma source. In preferredembodiments, each form of plasma is independently controlled to cover awide spectrum of processing conditions in a manner to satisfy thecomplexity and diversity of these residues. The present inventionpreferably involves placing the substrate (wafer or other article, etc.)in the plasma reactor, applying to the substrate surface an activatedmixture of gases selected from the group consisting of oxygen, nitrogen,hydrogen, fluorine, hydrofluorocarbon or a mixture of such gases to bothremove the photoresist layer and alter the composition of the residuessuch that the residues are soluble in water and/or have a weakened bondsthat they can be removed with a stream of cryogenic cleaning medium.

With respect to the cryogenic cleaning assembly, a nozzle having anozzle axis and a nozzle tip preferably is spaced from and adjacent tothe predetermined path for delivering a cleaning spray onto the articlesurface. Means preferably is mounted between the framework and thenozzle for supporting and driving the nozzle tip through a cyclicmotion.

In yet another aspect of the present invention, an oscillating orvibratory nozzle assembly for use in cryogenic cleaning of a surface ofan article that must be cleaned substantially free of contaminants isprovided, particularly after or as part of a dry process as describedherein. An oscillating nozzle assembly in accordance with certainpreferred embodiments preferably includes an assembly mounting block, anozzle mounting block, and means for resiliently connecting the nozzlemounting block to the assembly mounting block. Further, the oscillatingnozzle assembly preferably includes an eccentric and a driver connectedto the eccentric. In addition, means preferably is provided for mountingthe eccentric and the driver between the nozzle mounting block and theassembly mounting block. At least one nozzle preferably is includedhaving a nozzle tip, wherein the nozzle is mounted on the nozzlemounting block so that the driver operates to move the nozzle tipcyclically when the driver is energized. Alternatively, the oscillationcan be accomplished by actuators that support the nozzle or nozzlemounting block.

In yet another aspect of the present invention, the oscillating nozzleassembly for dispensing a cleaning medium toward a surface on an articlepreferably includes a nozzle, a tip on the nozzle for dispensing thecleaning medium, and means for mounting the nozzle. A nozzle assemblybase preferably is included together with means for controllably movingthe means for mounting the nozzle relative to the nozzle assembly basein a cyclic pattern having a predetermined frequency and amplitude.

Methods in accordance with preferred embodiments of the presentinvention relate to processing an article having a surface to be cleanedsubstantially free of contaminates. The process includes the steps ofperforming a plasma etching/ashing process, preferably to remove aphotoresist-type layer, a plurality of pre-cleaning fabrication steps,conducting a cleaning process at a cleaning position using a cleaningspray, and performing a plurality of post-cleaning fabrication steps.The plasma step preferably involves placing the substrate (or otherarticle) in the plasma reactor, applying to the substrate surface anactivated mixture of gases selected from the group consisting of oxygen,nitrogen, hydrogen, fluorine, hydrofluorocarbon or a mixture of suchgases to both remove the photoresist layer and alter the composition ofthe residues such that the residues are soluble in water and/or have aweakened bonds that they can be removed with a stream of cryogenicmedium.

The step of conducting a cleaning process preferably includes the stepsof transporting the surface to be cleaned to the cleaning positiontogether with positioning the surface to be cleaned proximate to thecleaning spray at the cleaning position. Further, the step ofoscillating the cleaning spray at the cleaning position in apredetermined pattern preferably is performed to provide improvedcleaning in accordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be more fully understood by a description ofcertain preferred embodiments in conjunction with the attached drawingsin which:

FIG. 1 is a perspective showing one embodiment of the system of thepresent invention;

FIG. 2 is a schematic showing gas and vacuum paths for one embodiment ofthe system of the present invention;

FIG. 3 is a perspective of one embodiment of the spray nozzle assemblyof the present invention with the outer cover removed;

FIG. 4 is a perspective of another embodiment of the nozzle assembly ofthe present invention with the outer cover removed;

FIG. 5 is a perspective of an additional embodiment of the system of thepresent invention;

FIG. 6 is a block diagram relating to the process of the presentinvention;

FIG. 7 is another block diagram illustrating the details of the processof the present invention;

FIGS. 8A and 8B illustrate an assembly for providing remotely generatedplasma and/or an RF-generated plasma, with a preferably cryogeniccleaning assembly integrally provided therewith;

FIG. 9 illustrates an assembly for providing remotely generated plasmaand/or an RF-generated plasma, with a preferably cryogenic cleaningassembly provided separate therefrom, with the article transported inorder to be cryogenically cleaned;

FIG. 10 illustrates an assembly for providing remotely generated plasmaand/or an RF-generated plasma, with a preferably cryogenic cleaningassembly utilizing a common showerhead-type electrode;

FIGS. 11A and 11B illustrate two alternative nozzle assemblies utilizedin certain preferred embodiments;

FIG. 12 illustrates a showerhead-type gas distribution implementutilized in certain preferred embodiments; and

FIG. 13 is a simplified flow diagram illustrating certain preferredprocess flows in accordance with certain embodiments of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described in greater detail with referenceto certain preferred embodiments and certain other embodiments, whichmay serve to further the understanding of preferred embodiments of thepresent invention. As described elsewhere herein, various refinementsand substitutions of the various embodiments are possible based on theprinciples and teachings herein.

The present invention generally is related to the following pending U.S.patent Applicants assigned to the assignee of the present invention:METHODS FOR CLEANING SURFACES SUBSTANTIALLY FREE OF CONTAMINANTS,application Ser. No. 09/636,265, filed on Aug. 10, 2000, and APPARATUSFOR CLEANING SURFACES SUBSTANTIALLY FREE OF CONTAMINANTS, applicationSer. No. 09/637,333, also filed on Aug. 10, 2000 (collectively, “theReferenced Applications”). The Referenced Applications more generallydisclosed methods and systems for cryogenically (preferably using carbondioxide) cleaning articles or surfaces substantially free fromcontaminants, preferably using an oscillatory nozzle assembly for thecryogenic cleaning medium. As the present invention, in at least certainpreferred embodiments, also utilizes an oscillatory or vibratory typenozzle assembly for a cryogenic cleaning medium (preferably incombination with a remotely-generated plasma and/or an RF plasmautilized preferably for removal of a photoresist or similar layer),certain disclosure from the Referenced Application will be set forthherein. The Referenced Applications are hereby incorporated byreference.

The present invention, however, preferably utilizes such an oscillatoryor vibratory cryogenic cleaning assembly in combination with a plasmaprocess; in alternative embodiments, the cryogenic cleaning implement isprovided in combination with the plasma process, where the oscillatoryor vibratory aspect of the cryogenic cleaning assembly is optionallyprovided (i.e., in such embodiments, the cryogenic cleaning medium mayor may not be provided with oscillatory or vibratory action, etc.).

Very small quantities of contamination generally are detrimental to thefabrication processes involved in producing integrated circuit wafers,hard discs, optical elements, etc. Contamination in the form ofparticulates, films, or microscopic clusters of molecules can producefatal defects in any of the aforementioned products before, during orafter fabrication processes. Cleanliness with elevated temperatureprocesses is extremely important due to the typical increase in thereaction rate of impurities with an increase in temperature. At hightemperature it is possible for the impurities to diffuse into thesilicon or mix with dielectric or conductors to cause unexpected andunwanted electrical or other characteristics. This tends to cause devicefailure, degraded reliability, and/or operational failure. Cleaning ofthe surfaces of such products is therefore essential at various phasesduring fabrication.

The use of plasma chemistry has become very important in thesemiconductor manufacturing sector. In photoresist stripping, the plasmaused in a dry process typically is performed using free radicals. Thisprocess is usually enhanced by a physical means to improve materialremoval and cleaning efficiency, often using an ion bombardment process.There are many shortcomings of the aforementioned combination, such asthe conflict of the relatively high pressure requirement for theeffectiveness of the pure chemical stripping and the ion bombardmentprocesses that require low pressure to increase the ions mean free path.Another problem with the ion bombardment process is that charging damagecould occur and cause wafer defects.

In accordance with preferred embodiments of the present invention, aplasma process is provided in conjunction with cryogenic cleaning forthe physical removal of contamination. In accordance with the presentinvention, such an approach tends to eliminate the pressure conflictdescribed elsewhere herein and tends to drastically reduce the chargingdamage problem. Without being bound by theory, this is believed to bedue to the pressure upstream of the nozzle not being very critical inthe cryogenic expansion. In addition, in accordance with the presentinvention, the process preferably is regulated for maximum efficiency bycontrolling the upstream pressure, velocity, temperature, and thefrequency and the amplitude of the nozzle vibration or oscillation.

Cryogenic cleaning of surfaces utilizing impingement of solid particlesof relatively inert gases such as argon and CO₂ are known and the mannerin which solid particles of such gases are generated for cleaningpurposes need not be described herein. Without being bound by theory, insuch cases it is thought that the combination of sublimation of thesolid particles as they impinge the surface to be cleaned as well as theimpact momentum transfer by the particles provide the vehicle forremoving contamination from a surface. It is further recognized thatsublimation occurs, and therefore a major portion of the cleaning, onlywhile the surface to be cleaned is at a higher temperature than that ofthe cryogenic spray. The thermophoresis due to the heated surface alsohelps to remove the particles from the surface and reduce the chance forre-deposition of the detached particles. As a consequence, pre-heatingand post-heating of the surface being cleaned preferably is requiredwithin the vicinity of the impinging cleaning spray. In accordance withpreferred embodiments of the present invention, preheating and postheating for the cryogenic cleaning are optional. Another importantaspect of single chamber processes with the combination of plasma andcryogenic cleaning is the elimination of contamination that in certainsituations tends to be deposited on the wafer with cryogenic cleaningalone. Without being bound by theory, the sources of the contaminantsare believed the delivery system and impurities that exist in thecryogenic cleaning medium; those impurities are believed to be composedof fluorinated and other hydrocarbons. The fact that the plasma gasesare used to clean fluorinated hydrocarbons tend to eliminate thisproblem. Cleaning by various other solvents and solvent combinationswhere the levels of residual contaminants following the cleaning processneed not be held quite as low, is also envisioned for use in the systemsand methods of the present invention.

As previously explained, certain disclosure from the ReferencedApplications will now be provided so that an exemplary, preferredoscillatory cryogenic cleaning assembly and method might be understood.

Reference is now made to FIG. 1 of the drawings, wherein one exemplaryembodiment of the present invention is illustrated. A system 10 is shownin FIG. 1 having an enclosure 11 depicted in phantom line. Theenvironment within the enclosure is maintained at a level of cleanlinessdepending on the level of cleanliness to be imposed on articles to becleaned within the enclosure. A scavenging line 12 is shown exiting theenclosure 11 at the bottom thereof and proceeding to a filter 13 forremoving particulates from the enclosure environment that may begenerated by the cleaning process or by mechanical components within theenclosure. Rudimentary support structure is shown including a base plate14 and two uprights 16 and 17 attached at their bases to the base plate.The description herein makes reference to an XYZ coordinate system,wherein the Z direction is substantially vertical and the mutuallyorthogonal Z and Y axes are substantially horizontal. An XY stage isshown having an X stage 18 for movement on a Y stage 19, that is mountedon the base plate 14 (other X/Y stage configurations are within thescope of the present invention). A holding chuck 21, in this instance avacuum chuck connected through a line 22 to a vacuum source 23, ismounted for movement on the X stage 18. An article to be cleaned, inthis exemplary illustration an integrated circuit wafer 24, is shown inFIG. 1 mounted to the vacuum chuck 21 and held in place by known means(e.g., held in place by the vacuum). FIG. 1 shows the integrated circuitwafer 24 in an initial position, and subsequently in a cleaning positionat 24 a and a post-heating position at 24 b. The integrated circuitwafer 24 preferably is transportable along a predetermined path governedby the movement of the X stage 18 on the Y stage 19 and the movement ofthe vacuum chuck 21 on the X stage 18. Chuck 21 is driven over the uppersurface of the X stage by known means, which may include a carriageportion within the X stage driven by a lead screw and a servo motor (notshown), for example. A cable connection 26 is shown at one end of the Xstage for introducing power to energize the aforementioned servo motor.A similar cable connection (not shown) is provided to power the Y stage19 so that the X stage, mounted on a moveable carriage of the Y stage,may be moved in the Y direction by a lead screw and servo motor similarto that mentioned hereinbefore in conjunction with the X stage.

From the foregoing it is seen that the integrated circuit wafer 24 shownin an initial position in FIG. 1 may be moved to the left in FIG. 1 topass beneath a pre-heater 27 at a pre-heat position along theaforementioned predetermined path, which preferably pre-heats theintegrated circuit wafer prior to cleaning. Further movement of thechuck 21 brings the integrated circuit wafer to a cleaning positionindicated in FIG. 1 at 24 a. Continuing movement of the chuck along thepredetermined path defined by the X and Y stages 18 and 19 delivers theintegrated circuit wafer to a post-heat position shown at 24 b, whereinpost-heating of the integrated circuit wafer preferably is performed bya post-beater 28. The pre and post heaters may be infrared lamps orother heating sources. These heaters preferably impart surfacetemperatures to the article that enhance cleaning, preventre-contamination and remove static electricity. In alternativeembodiments, the pre and post heaters are supplemented with, or replacedby, a heated vacuum chuck, with the heated vacuum chuck providing heatto the article to be cleaned, etc. The use of such a heated vacuum chuckalso may be used in accordance with other embodiments of the presentinvention as described herein.

A nozzle assembly support plate 29 is shown extending between the twouprights 16 and 17. The support plate preferably is attached at theupright 16 in a Z position by a friction clamp 31. The support plate 29preferably is mounted on the opposing end to upright 17 in the Zposition by an additional friction clamp 32. It should be noted that theposition of the mounting plate 29 in the Z direction may be governed bya servo motor 33 and associated mechanism (not shown) similar to that ofthe X and Y stages, so that the Z position of the support plate 29 isdictated by a control 34, which may controllably raise or lower thesupport plate 29 either before, during or after cleaning or otherprocessing.

A spray nozzle assembly 36 is shown mounted to the support plate 29 at apivot 37. A nozzle 38 is shown extending from the spray nozzle assembly36 at a lower portion thereof at the cleaning position shown by theposition of integrated circuit wafer 24 a in FIG. 1. A preferredexemplary angle of the nozzle 38 to the surface to be cleaned on theintegrated circuit wafer 24 is seen in FIG. 1 to be obtuse to thedirection of approach of the integrated circuit wafer. Expressedalternatively, the angle of the nozzle 38, and the subsequent sprayemitted therefrom, is acute to the downstream portion of thepredetermined path along which the wafer travels on the XY stage. Thepoint to be made here is that the spray emanating from the spray nozzle38 preferably is set to impinge the surface to be cleaned at an angle tofacilitate contaminant removal and to add any velocity of the surface tobe cleaned to the spray velocity for purposes of enhancing contaminantremoval. That angle of impingement as seen in FIG. 1 preferably isadjustable by moving the spray nozzle assembly 36 rotationally about thepivot 37 and fixing the angle in the adjusted position.

It should also be noted that, in preferred embodiments, one or more jetsfor cleaning an article, with the oscillatory-type movement of thepresent invention, such jets, although having a non-uniform spraypattern, may result in a more substantially uniform and improved spraydistribution due to the oscillatory-type movement, which preferablyenables an article to be more uniformly cleaned in a single pass, etc.

Turning to the diagram of FIG. 2, the spray nozzle assembly 36 is shownpoised in position above the integrated circuit wafer in the positionrepresented by 24 a wherein the wafer is moving to the left in FIG. 2relative to the spray nozzle assembly. Nozzle 38 is shown directing acleaning spray 39 onto the surface of the article to be cleaned(integrated circuit wafer 24 a in FIG. 2) at the spray impingement anglereferred to hereinbefore in conjunction with FIG. 1. A second spraynozzle 41 is shown just visible in the diagram of FIG. 2 for preferablydelivering a heated inert gas spray 42 for heating, drying and removingstatic electricity from the surface just cleaned by the spray 39. Theheated inert gas spray nozzle 41 may fill the requirements of thepost-heater 28 shown in FIG. 1. Details of construction of the nozzles38 and 41 will be described in more detail hereinafter.

FIG. 2 shows an inert gas source 43 connected through a flow line to atemperature control module 44 and subsequently to a gas filter 46. Inertgas flow is subsequently directed through an ionizer 47 and a flexibleline 48 to the nozzle 41 contained in the spray nozzle assembly 36. Acleaning medium container 49 (such as an argon or CO₂ gas container)preferably is connected through a gas flow line to a temperature control51. The temperature controlled cleaning medium preferably is connectedto a pressure booster 52 and subsequently to a filter 53 for removingcontaminants. The filtered, temperature controlled and pressurizedcleaning medium preferably is connected through a flexible line 54 tothe nozzle 38 in the spray nozzle assembly 36. The manner in which a gascleaning medium is conditioned for cryogenic cleaning is known, andteachings from the art submitted contemporaneously herewith areincorporated herein by reference. In certain applications the cleaningmedium contained in the container 49 may be a solvent different from thecryogenic gas, known to those in this art, descriptions of which willnot be undertaken here. A flexible vacuum line 56 is shown in FIG. 2 toremove contaminants generated by functions taking place within the caseof the spray nozzle assembly 36 so that they are not deposited upon thesurface to be cleaned. The flexible vacuum line 56 is led to the outsideof the enclosure 11 when the system containing the spray nozzle assembly36 is enclosed therein. The location of the pivot 37 of FIG. 1 is shownby the hole 37 a depicted in FIG. 2.

FIG. 3 depicts the spray nozzle assembly 36 with the cover removed. Thearticle to be cleaned represented by the integrated circuit wafer 24 ais seen to be moving to the left in FIG. 3 relative to the spray nozzleassembly. The spray nozzle assembly is pivoted about the pivot 37(FIG. 1) to assume the position shown in FIG. 3 so that the cleaningnozzle 38 dispenses the cleaning spray 39 at an obtuse angle relative tothe approaching portion of the surface to be cleaned. The cleaningnozzle 38 preferably has a nozzle axis and a nozzle tip with anelongated nozzle opening therein to provide the exemplary preferredfan-shaped spray 39 seen in FIG. 3. A friction lock 57 is shown on thenozzle 38 which allows the tip of the nozzle to be rotated around thenozzle axis and to be locked in the rotated position. Rotation of thetip of nozzle 38 preferably allows the fan-shaped spray 39 to impingethe surface to be cleaned at an angle of rotation about the nozzle axis.This angle of rotation allows the fan-shaped spray 39 to pushcontaminates to one side of the surface to be cleaned as to the spraynozzle is oscillated to thereby affect a “snow plow” function. This willbe further explained in conjunction with the description of theoscillation of the nozzle 38. In like fashion, nozzle 41 for dispensinginert drying gas, preferably has a friction lock 58 functioning in thesame manner as the friction lock 57 on nozzle 38. Nozzle 41 also has atip with an elongated opening therein for preferably producing a fanshaped emission of inert drying gas 42. Nozzle 38 preferably is attachedto a nozzle mounting block 59 through a tube 61 and a connector 62coupling the nozzle 38 to the flexible line 54 (FIG. 2). Nozzle 41 alsopreferably has a tube 63 connected thereto which is mounted in thenozzle mounting block 59. A connector 64 connects the tube 63 to theflexible line 48 (FIG. 2) to deliver heated inert gas to the surface tobe cleaned immediately after cleaning when that method is used forpost-heating of and removal of static charge from the surface beingcleaned.

Nozzle mounting block 59 in FIG. 3 is cut away to show installation ofthe outer diameter of an outer bearing race 66 mounted within a bore 67in the nozzle mounting block. An inner race 68 on the bearing within thebore 67 has an eccentric cam-member 69 mounted therein. A shaft 71 on apulley 72 is passed through an offset hole 73 in the eccentric cam andfixed therein. The pulley 72 is driven by a belt 74 which in turn isdriven by a pulley 76 mounted on the end of a shaft 77 driven by a motor78. The motor 78 is mounted in a motor mount block 79 (partly cut awayfor clarity) secured to the outer case of the spray nozzle assembly 36.The motor mount block 79 also serves to mount the pulley 72 for rotationthereon. A plurality of arms 81, two of which are shown in FIG. 3, arefastened to the motor mounting block 79 extending outwardly therefrom toa position beyond the nozzle mounting block 59. Yieldable structure suchas coil springs 82, extend from the ends of the arms 81 to the nozzlemounting block 59 and from the motor mounting block 79 to the opposingside of the nozzle mounting block 59. The ends of the coil springs 82are encompassed by buttons or caps 83 that are seated in counter boresin the structural members 59, 79 and 81 that receive respective ends ofthe coil springs 82. The material for the end caps 83 is preferablyDelrin AF. Very little particulate is sloughed off of the Delrin AFsurfaces when the material is subjected to friction. As a result, thesprings 82 are anchored on one end within the bores 84 at the ends ofthe arms 81 and in the motor mounting block 79 and anchored at anopposing end within bores 84 in the nozzle mounting block 59. Nozzlemounting block 59 is therefore suspended by the springs 82 in positionspaced from the remainder of the spray nozzle assembly. Consequently,when the spray nozzles 38 and 41 are mounted on the nozzle mountingblock 59, and when the nozzle mounting block is moved, the sprays 39 and42 are moved relative to the surface to be cleaned on the integratedcircuit wafer 24 a in FIG. 3. An optimum offset from the geometriccenter of the offset cam 69 has been found to be about 0.075 inches. Asa result an optimum peak to peak amplitude for cam excursion is about0.150 inches. An optimum cam rotation frequency through the pulleys 76and 72 has been found to be approximately 27.5 revolutions per second orabout 27½ Hertz. Thus, in a preferred embodiment, the optimum amplitudeprovided by the cam 69 falls within the range of about 0.120 to 0.180inches peak to peak. The optimum frequency falls within the range ofabout 25 to 30 Hertz. Other amplitudes and frequencies for optimumcleaning of specific contaminants from surfaces are envisioned as withinthe scope of the present invention.

Springs 82, in this preferred embodiment, preferably have coils of 0.043inch diameter stainless steel wire, with one half (½) inch diametercoils and lengths of one and one-half (1½) inches. Such springsgenerally should provide adequately support the mass of the nozzlemounting block 59 and members attached thereto. It should further benoted that motor 78 could be mounted on motor mounting block 79 todirectly drive shaft 71 connected to the eccentric cam 69 in thoseinstances where the rotational output speed of the motor shaft 77imparts an acceptable frequency to the oscillatory motion induced by therotation of the eccentric cam 69. In any event, the nozzle mountingblock 59 and the nozzles 38 and 41 attached thereto are driven at apredetermined frequency and amplitude, so that the nozzles are driven ina circular pattern having a diameter of the peak to peak oscillationamplitude and a frequency determined by the rotational frequency of theeccentric cam 69. The physical dimensions of springs 82 will depend onthe mass of the spray nozzle assembly 36. Therefore, heavier or lightersprings 82 may be used as the spray nozzle assembly assumes greater orlesser mass. It is noted that the preferred structure for imparting thecyclic motion to the nozzles 38 and 41 relative to the surface to becleaned are exemplary.

FIG. 4 depicts the spray nozzle assembly 36 with the motor mountingblock 79 removed from the drawing for clarity. As seen in FIG. 4, asingle nozzle 38 is shown having the aforementioned preferred elongatedaperture therein for providing emission of the fan-shaped spray 39 forimpingement on the surface to be cleaned. The surface shown in FIG. 4 isthe surface of the integrated circuit wafer 24 a. Friction lock 57 inthe illustration of FIG. 4 is loosened and the nozzle 38 is rotatedcounter-clockwise (looking at the elongated aperture therein). Theorientation of the aperture of nozzle 38 is locked in the adjustedposition by the friction lock 57. When the motor 78 is energized and anoscillation in the nozzle 38 is imparted by the oscillation of thenozzle mounting block 59 on the support provided by the springs 82, thenozzle tip, and therefore the spray 39 describes a circular pattern atthe predetermined amplitude and frequency. The rotation of theoscillation is indicated by the arrow 84 in FIG. 4.

The impingement of the spray pattern 39 on the surface to be cleaned isillustrated in FIG. 4. The nozzle 38 and the spray pattern 39 movesduring half of each rotational cycle toward the integrated circuitwafer. Further, during the subsequent half of each rotational cycle thenozzle and spray move away from the wafer surface. This is seen when itis recognized that the nozzle tip describes a circle during oscillation,wherein the plane of the circle substantially includes an extension ofthe nozzle axis. This is illustrated in FIG. 4 by the rotational arrow84 and the arrows 85 representing oscillation circle diameters. Thenozzle 38 sweeps the spray 39 side to side on the wafer surface becausethe edge of the circle represented by diameters 85 appears as a straightline when viewed from the wafer surface.

Now considering the rotation of the flat fan shaped spray 39 about thenozzle axis by the adjustment of the friction lock 57, the fan 39impinges the surface at a compound angle (displaced from the side toside sweep) preferably resulting in the “snow plow” effect of thefan-shaped spray 39 during half of each cycle as it rotates in thedirection of the arrow 84. Further, the disclosed oscillation of thefan-shaped spray 39 provides the benefits of pulsing which enhancescleaning. Pulsing in the past has been provided in a spray byinterrupting the spray periodically. However, such interruption causesthe spray jet to lose optimum characteristics as the spray is cut offand restarted when the spray is a cryogenic cleaning medium comprised ofsolid gas particles. The pulsing occurs in the embodiments disclosedherein due to increasing velocity (or acceleration) as the spray 39converges on the surface to be cleaned during one half (½) of theoscillatory cycle and the decrease in velocity (negative acceleration)as the spray 39 diverges from the surface to be cleaned during the otherhalf of the oscillatory cycle. Spray nozzle 38 describing a circularpattern during oscillation as described hereinbefore, preferably laysdown a laterally oscillating spray pattern on the surface to be cleaned.The angle of the spray pattern impingement on the surface is thereforeformed by adjustment of the spray nozzle assembly 36 rotationally aboutthe pivot 37 (FIG. 1) and adjustment to the spray fan orientation aboutthe nozzle axis through adjustment of the friction lock 57. Pulsing andcompound angle “snow plow” effects in cleaning are believed to provideadvantages in obtaining thorough contaminant removal. It should bementioned that the shaft 71 for driving the eccentric cam 69 (FIG. 3)could be driven directly by the motor 78, allowing elimination of thepulleys 72 and 76 and the belt 74 as discussed in conjunction with FIG.3. On the other hand, selection of relative diameters of pulleys 72 and76 may be used to adjust the frequency of oscillation if desired.

The embodiment of FIG. 5 depicts a robot 86 having an extendable andretractable arm 87, providing movement in a vertical direction, and alaterally extending arm segment 88 disposed for rotation about an axis89 at the upper end of the arm 87. An additional robot arm 91 isprovided that moves translationally in a horizontal direction.Translationally moving arm 91 extends through an egress/ingress port 92in the enclosure 11 of FIG. 5 to insert an article having a surface tobe cleaned, such as the integrated circuit wafer 24, into a controlledenvironment within the enclosure 11 as discussed in conjunction with theenclosure 11 of FIG. 1. The wafer 24 is shown at the limit of itsinsertion within the enclosure 11, having passed the pre-heater andpost-heater combination 93 immediately inside the ingress/egress port.Wafer 24 is therefore pre-heated at the position shown in FIG. 5 andthen withdrawn toward the ingress/egress port 92 to pass beneath a bank(plurality) of cleaning nozzles 94. The bank of nozzles extend acrossthe entire dimension of the wafer, providing impingement by a pluralityof fan shaped sprays on the surface to be cleaned, thereby cleaning thesurface in a single pass beneath the bank of cleaning nozzles 94.Immediately following passage of the surface to be cleaned beneath thecleaning nozzles 94, an inert drying gas and anti-static electricityarray 96 is positioned that also extends across the entire dimension ofthe wafer 24. As the wafer is withdrawn toward the ingress/egress port92, the surface is dried by the inert drying gas nozzle array andfurther heated by the pre/post heater 93 to a temperature that willprohibit condensation on the clean surface as it is withdrawn from theenclosure 11 by the robot arm 91. Positioned adjacent the cleaningnozzle array 94 is a scavenging intake 97 that operates to removeparticulates cleaned from the surface of the wafer 94 as well asparticulates generated within the enclosure 11. Scavenging intake isconnected to an exhaust 98, which carries the contaminants from withinthe enclosure to the ambient environment. Pressure within the enclosure11 preferably is maintained slightly higher than ambient pressure toprevent contaminants from entering the enclosure through theingress/egress port 92. Further, as in the description of the embodimentof FIG. 1, the scavenging line 12 is provided to withdraw the enclosedatmosphere and deliver it to the cleaning filter 13 to further reducecontaminants within the enclosure.

With regard to an exemplary preferred method in accordance with thepresent invention, there preferably exist certain pre-cleaningfabrication steps for the article having a surface to be cleanedfollowed by the step of cleaning the surface, and culminating inpost-cleaning fabrication steps for the article having a surface to becleaned. The block diagram of FIG. 6 depicts these steps. Details of apreferred surface cleaning process of FIG. 6 are found in the blockdiagram of FIG. 7. FIG. 7 illustrates the pre-cleaning fabrication stepsof FIG. 6 followed by mounting the article having a surface to becleaned on an article transport. In one embodiment of the cleaningprocess the article is transported to a cleaning position and the shapeof the spray is configured to assume a fan shape. The spray nozzle inthen oriented to cause the spray to impinge the surface to be cleaned atan angle to the lateral dimension of the surface as it passes the spray.This angle is called a compound angle. The nozzle is then aimed at thesurface to be cleaned to form an obtuse angle with the surface relativeto the approaching portion of the surface to be cleaned. Subsequently,the nozzle is oscillated so that the spray functions as a pulsing sprayas the forward motion of the nozzle is added to the velocity of thecleaning spray during one portion of the oscillation cycle and issubtracted from the velocity of the cleaning spray during the subsequentportion of the oscillation cycle. Moreover, the orientation of thenozzle aperture and the fan-shaped spray about the nozzle axispreferably provides a “snow plow” effect facilitating cleaning aspreviously described. Subsequent to the cleaning by the oscillatingfan-shaped spray the article preferably is moved onto the post-cleaningfabrication steps as illustrated in FIG. 7.

In another aspect of the cleaning process of the present invention acryogenic cleaning medium is used. As mentioned hereinbefore an inertgas such as argon or CO₂ is in substantially solid or “snow” form as itis emitted from the nozzle so that sublimation of the gas occurs at thesurface to be cleaned. In this process the surface to be cleanedpreferably is preheated to a temperature such that the surface to becleaned will remain at a temperature above ambient during theimpingement of the cryogenic spray on the surface. The spray preferablyis shaped into a fan shape and the spray nozzle aperture preferably isoriented about the nozzle access to provide impingement of the fan sprayon the surface to be cleaned at an angle to the lateral dimension of thesurface (the compound angle). The spray nozzle preferably is then aimedat the surface at an obtuse angle relative to the surface portionapproaching the cleaning spray and the nozzle preferably is oscillatedin a cyclic pattern having a pre-determined amplitude and frequency. Thenozzle preferably oscillates in a substantially circular pattern in aplane including the nozzle axis so that the spray pattern is lateral andlinear on the surface. Moreover, due to the orientation of the nozzlerotationally about the nozzle axis, the spray impinges the surface atthe compound angle and performs a “snow plow” function. This function isbelieved to tend to push contaminants to one side of the surface to becleaned. Following exposure to the oscillation cleaning spray, thesurface preferably is post-heated to a temperature above ambienttemperature to prevent condensation and recontamination of the surfaceand also to remove static charge. It should be noted that the step ofshaping the spray preferably reside in both embodiments of the processdescribed in conjunction with FIG. 7 and includes expanding the width ofthe cleaning spray to cover the lateral dimension of the surface to becleaned. As a result, the cleaning of the surface may be obtained in asingle pass of the surface to be cleaned past the spray. Subsequentlythe post-heated article surface is passed to the post-cleaningfabrication steps as seen in FIG. 7.

As previously explained, preferred embodiments of the present inventionare directed to the combination of plasma processing (such as removal orashing of a photoresist-type layer) that provides a chemical mechanism,followed by a cryogenic cleaning processing that preferably provides aphysical removal-type mechanism. While oscillatory or vibratory-typecryogenic cleaning is believed to provide more optimum results incertain embodiments, the present invention as set forth herein isexpressly not limited to the use of oscillatory or vibratory typecryogenic cleaning, and certain embodiments of the present inventionutilize cryogenic cleaning that is not oscillatory or vibratory.Accordingly, the foregoing description from the Referenced Applicationsis provided as background and for providing a description of anexemplary oscillatory assembly used only in certain embodiments of thepresent invention.

Turning now to FIGS. 8A and 8B, exemplary preferred embodiments of thepresent invention will now be described.

Referring to FIG. 8A, gas source 104 provides a source of reactant gas,which in preferred embodiments may consist of, for example, gasesselected from the group consisting of oxygen, nitrogen, hydrogen,fluorine, hydrofluorocarbon or a mixture of such gases, representativeexamples being O2, N2, H2, CF4 and NF3, etc. The reactant gas(es)preferably is/are provided through compressed cylinder(s) such as isillustrated by gas source 104 (hereinafter, the reactant gas or gases orreferred to simply as the “reactant gas”). In preferred embodiments, thereactant gas is supplied via mass flow controller(s) 105 (which serve tocontrol the flow of the reactant gas) and pipe 102 to plasma applicator103, which in preferred embodiments consists of a microwave dischargeapparatus, which includes or is coupled to microwave source 103A.Microwave source 103A and plasma applicator/microwave discharge 103create free radicals from the reactant gas, which may then be suppliedto vacuum processing chamber 101. The reactant gas free radicalspreferably are introduced into processing chamber 101 via a gasdistribution system or implement, which in FIG. 8A is illustrated asshowerhead 108, such that the activated reactant gas/free radicals arepresented to, and may react with, material of the article beingprocessed (indicated as wafer 109 in FIG. 8A, which has been introducedinto processing chamber 101 as illustrated).

In preferred embodiments, heated wafer holder 110 is provided overheating implement 111, which optionally provides heat preferably via anelectric heating element from the back side of wafer 109, in a manner asis known in the art. As will be appreciated, heating implement 111 maybe controlled to provide the proper and optimum temperature for theparticular process. Pressure within processing chamber 101 is controlledin part via exhaust pump 106, which is in flow communication withprocessing chamber 101 via exhaust pipe 107.

It also should be noted that RF source 101A is optionally provided asillustrated. In such embodiments, wafer holder 110 preferably serves asa first electrode, and a second electrode is provided, which may consistof the housing of processing chamber 101 or showerhead 108 asillustrated in FIG. 8A. In accordance with certain embodiments of thepresent invention, RF source 101A provides RF energy that creates an RFplasma that produces radicals and ions from the reactant gas that areprovided to wafer 109, such as for ashing or removing a photoresist-typelayer on wafer 109. In certain embodiments, only an RF plasma isutilized (and thus the remote plasma discharge 103 is not provided oroperative), while in other embodiments only the radicals produced byremote plasma discharge 103 are utilized (and thus RF source and/or thefirst and second electrodes are not provided or are not operative),while in yet other embodiments both the RF plasma and the radicalsproduced by remote plasma discharge 103 are utilized. It should beunderstood that the RF plasma and electrodes may be biased andcontrolled such that what is known as an RIE process may be carried out,although the present invention is not limited thereto. What is importantis that one or more plasma/free radical sources are provided to deliverthe reactant gas species to the surface of wafer 109 such that thephotoresist or similar layer thereon may be attacked chemically (whichmay have a physical component as well, in the case of an RIE process) soas to ash or remove the photoresist layer. An exemplary disclosure ofsuch an apparatus having a microwave discharge implement and an RF/RIEplasma is U.S. Pat. No. 5,795,831, which is hereby incorporated byreference for background purposes.

In conventional approaches, a de-ionized water or solvent process isprovided after plasma treatment in order to remove residue resultingfrom the plasma process. The necessity of such a DI water and/or solventcleaning has been determined to be detrimental to optimum processing,and in accordance with embodiments of the present invention a cryogeniccleaning process is performed as part of, or subsequent to, the plasmaprocess. As illustrated in FIG. 8A, nozzle/nozzle assembly 112 isprovided with a transport mechanism that moves nozzle/nozzle assembly112 relative to wafer 109 in a manner such that the cryogenic cleaningmedium (preferably consisting of or including carbon dioxide) impingeson and over the surface of wafer 109. The use of the cryogenic cleaningprocess, in combination with the remotely-generated and/or RF generatedplasma, has been determined to provide more optimum removal ofphotoresist-type layers.

In accordance with certain preferred embodiments, an oscillatory orvibratory discharge of the cryogenic cleaning medium is provided inorder to provide more optimum cleaning. While the ReferencedApplications described exemplary ways of implementing such anoscillatory or vibratory mechanism, the embodiment illustrated in FIG.8A illustrates another exemplary mechanism. As illustrated in FIG. 8A,an oscillatory/vibratory nozzle cleaning system, preferably dispensingcryogenic, solvent or solvent combination cleaning medium(s) to assistthe plasma cleaning and photoresist stripping/removal process. Theoscillatory/vibratory nozzle cleaning and plasma processes can beperformed sequentially or simultaneously, as will be described ingreater detail hereinafter. In the illustrated embodiment, theoscillatory/vibratory nozzle cleaning system includes vibrationactuators 115, which are attached to nozzle manifold 113 to induce theoscillation or vibration. The oscillatory/vibrator nozzle cleaningsystem preferably is mounted on vibration isolators 116 to preventvibration of posts 114. Posts 114 (preferably two) are mounted on linearslide assembly 117 to allow nozzle/nozzle assembly to “sweep” wafer 109with the cryogenic cleaning medium. Nozzle manifold 113 preferablyutilizes a pressurized plenum to ensure uniform flow throughnozzle/nozzle assembly 112. It should be noted that theoscillatory/vibratory nozzle system of FIG. 8A is exemplary; what isimportant is that the process chamber include plasma treatmentcapability such as has been described, and also a preferably integraltype of cryogenic cleaning medium assembly that can movably or otherwiseprovide the cryogenic cleaning medium on and over the surface of wafer109.

In operation, wafer 109 is introduced into processing chamber 101; in anillustrated embodiment, wafer 109 includes a photoresist or similar-typelayer that needs to be removed. Plasma/free radicals are generated viathe reactant gas (either via plasma applicator/microwave discharge 103and/or an RF plasma, etc.), which preferably chemically attack andremove the material of the photoresist layer. In the case of reactantgas that is free radicalized via plasma applicator/microwave discharge103, free radicals and ions are generated from the reactant gas,although it is believed (without being bound by theory) that theconcentration of ions that are introduced into processing chamber 101 islow due to the relatively high operating pressure that may be utilized.Either subsequent to or interspersed with plasma processing steps, oneor more cryogenic cleaning steps are performed, which serve to remove(preferably with a mechanical type action) residues and contaminantsthat are present after the plasma/free radical treatment. Without beingbound by theory, it also is believed that plasma treatment subsequent toa cryogenic cleaning step helps remove residue that exists after thecryogenic cleaning step, and that the cryogenic cleaning subsequent to aplasma/free radical treatment helps remove residue that exists after theplasma treatment. In combination, it has been determined that suchcombined processing produces a more optimum photoresist-type layerremoval process, which may eliminate or substantially reduce the needfor a DI water or solvent rinse process.

FIG. 8B illustrates another view of the embodiment described inconnection with FIG. 8A (although for simplicity, for example, RF source101A has not been shown in FIG. 8B).

FIG. 8B illustrates an embodiment of nozzle/nozzle assembly in flowcommunication with nozzle manifold 113, and preferably positioned onvibration actuators 115 and vibration isolators 116, which in turn arepositioned on posts 114, the assemblage of which is movable via, forexample, linear slide assembly 117. Other aspects of FIG. 8B discussedin conjunction with FIG. 8A will not be further discussed.

In addition, FIGS. 8A and 8B illustrate a nozzle assembly, anotherexemplary preferred embodiment of which is illustrated in FIG. 11A. Asillustrated in FIG. 11A, cryogenic medium inlet 117 is provided, whichis in flow communication with pressure plenum 116. A perforated plate orsurface 118 is provided in flow communication with pressure plenum 116,such as is illustrated. As part of, or coupled to, perforated plate orsurface 118, but in any event in flow communication therewith, arepreferably axi-symmetric nozzles 119. Nozzles 119 may be holes of atapered or conical shape (or other shape to provide the desired nozzlecharacteristics) formed in a relatively thick plate (thick enough toaccommodate the desired nozzle shape and provide the necessarymechanical strength, etc.). Alternatively, as illustrated in FIG. 11B,perforated or slotted plate 118A may be provided, with planar nozzlesystem 118B provided. As illustrated, planar nozzle system 118B mayconsist of two inclined planes coupled to form a slotted or planarnozzle. Again, as will be appreciated, such a planar nozzle assemblywill have internal shapes and an exit orifice or orifices in order todistribute the cryogenic cleaning medium in a desired manner, etc.

FIG. 9 illustrates an alternative embodiment in which nozzle/nozzleassembly 112 is stationary, and wafer 109 moves relative tonozzle/nozzle assembly 112. In such an embodiment, wafer holder 110consists of, or is on, a movement mechanism such as a linear slideassembly such that after plasma processing, wafer 109 is moved relativeto nozzle/nozzle assembly 112 such that the cryogenic cleaning medium ispresented to the surface of wafer 109 such as has been previouslydescribed. Also as previously described, the cryogenic cleaning mediummay be delivered in an oscillatory or vibratory manner (although this isnot required in all embodiments), which may be via a mechanism suchdescribed in connection with FIGS. 8A and 8B, or which may be via theoscillatory mechanisms as described in the Referenced Applications (anddescribed above). Other aspects of the embodiment of FIG. 9 that are incommon with the embodiments of FIGS. 8A and 8B, including the use of anRF source to generate an RF/RIE type plasma treatment, which will not befurther described for purposes of convenience.

FIG. 10 illustrates a further alternative embodiment, wherein showerhead108 includes inlet 115 for purposes of introducing the cryogeniccleaning medium (e.g., carbon dioxide). In such embodiments, showerhead108 provides for delivery of free radicals generated from the reactantgas to the surface of wafer 109, while also providing for delivery ofthe cryogenic cleaning medium to the surface of wafer 109. In anillustrative operation of such an embodiment, a plasma/free radicaltreatment may be provided (which may be accompanied or substituted by anRF/RIE plasma treatment, such as previously described), which mayinvolve showerhead 108 distributing free radicals generated from thereactant gas at a first point in time (plasma treatment phase), anddistributing the cryogenic cleaning medium at a second point in time(cryogenic cleaning phase) (the distribution of free radicals and/orcryogenic cleaning medium is illustrated in FIG. 10 by spray pattern113). In certain embodiments, a single set of distribution holes areprovided in showerhead 108, with the reactant gas flow and the cryogeniccleaning medium flow alternatively turned on and off. As illustrated inFIG. 12, however, showerhead 120 may be provided, which includesseparate distribution holes for the plasma/free radicals (holes 122) andcryogenic cleaning nozzles (holes 121). In such embodiments, holes 122have a size and shape for the more optimum delivery of plasma/freeradicals, while holes 121 have a size and shape for the more optimumdelivery of the cryogenic cleaning medium. In one exemplary embodiment,the size of holes 122 is greater than the size of holes 121, andpreferably hole 121 are formed to provide a nozzle effect for thedispersal and distribution of the cryogenic cleaning medium, etc. As thecharacteristics of the medium passing through the holes, and the moreoptimum delivery conditions from the holes, are quite distinct, havingfirst and second holes of differing sizes and shapes and flowcharacteristics has been determined to provide more optimum results insuch embodiments.

FIG. 13 illustrates a general process flow in accordance with preferredembodiments of the present invention. As previously described, anarticle, wafer, substrate, etc. having a layer to be removed (e.g., aphotoresist-type layer) is introduced into the processing chamber. Thisgenerally is illustrated by start step 125. At step 126, a plasmatreatment step is provided, such as previously described. This mayconsist of plasma/free radicals remotely generated such as previouslydescribed, and/or an RF or RIE type plasma treatment, also such aspreviously described. At step 127, a cryogenic cleaning (e.g., carbondioxide) process is performed, such as previously described. This may bea two step, two phase process, where a single plasma phase/step 126 isperformed, and then a single cryogenic cleaning phase/step 127 isperformed, with the flow then stopping as illustrated by end step 131.In alternate embodiments, however, as indicated by flow path 130, aplasma treatment phase/step is provided followed by a cryogenic cleaningphase/step, with the plasma treatment-cryogenic cleaning steps repeateda plurality of times. In such embodiments, and without being bound bytheory, it is believed that the plasma treatment phase provides aprimarily chemical means for removal of the target material, while thecryogenic cleaning phase removes residues and materials present afterthe plasma treatment phase, and with a subsequent plasma treatment phasehelping remove residue and materials present after the cryogeniccleaning phase. While not illustrated in FIG. 13, in certain suchembodiments, the process begins and ends with a plasma treatment phase.

Although the invention has been described in conjunction with specificpreferred and other embodiments, it is evident that many substitutions,alternatives and variations will be apparent to those skilled in the artin light of the foregoing description. Accordingly, the invention isintended to embrace all of the alternatives and variations that fallwithin the spirit and scope of the appended claims. For example, itshould be understood that, in accordance with the various alternativeembodiments described herein, various systems, and uses and methodsbased on such systems, may be obtained. The various refinements andalternative and additional features also described may be combined toprovide additional advantageous combinations and the like in accordancewith the present invention. Also as will be understood by those skilledin the art based on the foregoing description, various aspects of thepreferred embodiments may be used in various subcombinations to achieveat least certain of the benefits and attributes described herein, andsuch subcombinations also are within the scope of the present invention.All such refinements, enhancements and further uses of the presentinvention are within the scope of the present invention.

What is claimed is:
 1. A method for manufacturing an article, thearticle having a resist layer to be removed during the manufacture ofthe article, comprising the steps of: generating free radicals from oneor more reactant gases remote from a processing chamber containing thearticle; introducing the free radicals into the processing chamber,wherein the free radicals react with the resist layer; and supplying acryogenic cleaning medium into the processing chamber, wherein thecryogenic cleaning medium removes residue present after the freeradicals react with the resist layer; wherein the reactant gases areselected to result in residue from the reaction with the resist layerhaving weakened bonds, wherein the residue is removed with the cryogeniccleaning medium; wherein the resist layer is removed from the article.2. The method of claim 1, further comprising the steps of: applying RFenergy to one or more electrodes in the processing chamber; generatingan RF plasma, wherein the RF plasma is generated from the reactant gasesand/or from the free radicals, wherein the RF plasma reacts with resistlayer; wherein the step of supplying a cryogenic cleaning mediumoperates to remove residue present after the RF plasma reacts with theresist layer.
 3. The method of claim 1, wherein one or more of theintroducing and supplying steps are repeated a plurality of times. 4.The method of claim 3, wherein at least one of the introducing steps isperformed after a predetermined supplying step, wherein the freeradicals react with residue present after the predetermined supplyingstep.
 5. The method of claim 1, wherein the cryogenic cleaning medium issupplied in an oscillatory or vibratory manner.
 6. A method formanufacturing an article, the article having a resist layer to beremoved during the manufacture of the article, comprising the steps of:applying RF energy to one or more electrodes in a processing chambercontaining the article; generating an RF plasma, wherein the RF plasmais generated based on one or more reactant gases, wherein the RF plasmareacts with the resist layer; supplying a cryogenic cleaning medium intothe processing chamber, wherein the cryogenic cleaning medium operatesto remove residue present after the RF plasma reacts with the resistlaser; wherein the reactant gases are selected to result in residue fromthe reaction with the resist layer having weakened bonds, wherein theresidue is removed with the cryogenic cleaning medium; wherein theresist layer is removed from the article.
 7. The method of claim 6,further comprising the steps of generating free radicals from the one ormore reactant gases remote from the processing chamber; introducing thefree radicals into the processing chamber, wherein the free radicalsreact with the resist layer; and wherein the step of supplying acryogenic cleaning medium operates to remove residue present after thefree radicals react with the resist layer.
 8. The method of claim 6,wherein one or more of the generating and supplying steps are repeated aplurality of times.
 9. The method of claim 8, wherein at least one ofthe generating steps is performed after a predetermined supplying step,wherein the RF plasma react with residue present after the predeterminedsupplying step.
 10. The method of claim 6, wherein the cryogeniccleaning medium is supplied in an oscillatory or vibratory manner. 11.The method of claim 1, wherein the reactant gases are selected to resultin removal of the residue with the cryogenic cleaning medium.
 12. Themethod of claim 1, wherein the reactant gases comprise gases selectedfrom the group consisting of oxygen, nitrogen, hydrogen, fluorine, andhydrofluoro carbon.
 13. The method of claim 12, wherein the reactantgases are selected to result in residue from the reaction with theresist layer having weekend bonds, wherein th residue is removed withthe cryogenic cleaning medium.
 14. The method of claim 12, wherein thereactant gases are selected to result in removal of the residue with thecryogenic cleaning medium.
 15. The method of claim 1, wherein thereactant gases comprise gases selected from the group consisting of O2,N2, H2, CF4 and NF3.
 16. The method of claim 15, wherein the reactantgases are selected to result in residue from the reaction with theresist layer having weekend bonds, wherein the residue is removed withthe cryogenic cleaning medium.
 17. The method of claim 15, wherein thereactant gases are selected to result in removal of the residue with thecryogenic cleaning medium.
 18. The method of claim 6, wherein thereactant gases are selected to result in removal of the residue with thecryogenic cleaning medium.
 19. The method of claim 6, wherein thereactant gases comprise gases selected from the group consisting ofoxygen, nitrogen, hydrogen, fluorine, and hydrofluoro carbon.
 20. Themethod of claim 19, wherein the reactant gases are selected to result inresidue from the reaction with the resist layer having weekend bonds,wherein the residue is removed with the cryogenic cleaning medium. 21.The method of claim 19, wherein the reactant gases are selected toresult in removal of the residue with the cryogenic cleaning medium. 22.The method of claim 6, wherein the reactant gases comprise selected fromthe group consisting of O2, N2, H2, CF4 and NF3.
 23. The method of claim22, wherein the reactant gases are selected to result in residue fromthe reaction with the resist layer having weekend bonds, wherein theresidue is removed with the cryogenic cleaning medium.
 24. The method ofclaim 22 wherein the reactant gases are selected to result in removal ofthe residue with the cryogenic cleaning medium.